The Witness in the L-Shaped Corridor

In the 5th-floor corridor of an 8-storey officetel in Seongbuk-gu, Byun Woo-hyuk, the resident of Unit 502, was found collapsed after being struck with a blunt object. From 19:48, when he completed an order on a delivery app, to 20:04, when the delivery rider found him and reported it — just 16 minutes is the window in which the crime was possible. The corridor CCTV had broken down three weeks earlier and was off, and the door-lock logs for the building's two entrances show no trace of an outsider coming in. During that time, it is said, a resident who claims to be a witness was standing on the smoking balcony at the north end of the 5th floor. And yet he says, 'Nobody came.'